Colourchecker passport

The Colourchecker Passport is what help achieve accurate colour in digital photography. Oddly enough, the camera or computer don't magically fix everything automatically as both have their own colour biases. For we humans colour is subjective, so it helps to have to have a standard by which to judge to get it as correct as possible; otherwise, it's a case of 'Now, just what shade of red do I remember his tie being?'